Dietary Selenium Concentrations Research Articles

Impact of dietary selenium and blood concentration on liver function: a population-based study.

Evidence on the association between selenium and liver function parameters is limited and controversial. Data on dietary selenium intake, blood selenium concentration, and liver function parameters were obtained from the National Health and Nutrition Examination Survey (NHANES) 2017-2020. Associations between selenium (dietary intake and blood concentration) and liver function parameters [alanine aminotransferase (ALT), aspartate aminotransferase (AST), the ALT/AST ratio, gamma-glutamyl transferase (GGT), and alkaline phosphatase (ALP)] were assessed using multivariate linear regression models. Subgroup analyses and interaction tests were conducted to examine differences in associations according to age, gender, body mass index (BMI), diabetes, and physical activity. The study included 6,869 participants after screening. The multivariate linear regression model revealed that dietary selenium intake was positively associated with ALT (β = 0.112, 95% CI = 0.041, 0.183) and the ALT/AST ratio (β = 0.002, 95% CI = 0.001, 0.004) after adjustment for covariates. Results of blood selenium concentration also showed that higher blood selenium levels were positively associated with ALT (β = 0.436, 95% CI = 0.308, 0.564), AST (β = 0.112, 95% CI = 0.015, 0.208), and the ALT/AST ratio (β = 0.012, 95% CI = 0.009, 0.015). However, ALP decreased with increasing blood selenium concentration (β = -0.207, 95% CI = -0.414, -0.000). In addition, we found significant differences in the effect of selenium on liver function parameters according to age, gender, and BMI. Dietary selenium intake and blood concentration affect liver function parameters. These findings suggest that further research is needed to explore these associations to promote liver health and disease prevention.

The Effects of Dietary Manganese and Selenium on Growth and the Fecal Microbiota of Nursery Piglets.

The objective of this study was to determine the impact of varying dietary manganese and selenium concentrations, antioxidant cofactors, on the growth performance and fecal microbial populations of nursery pigs. The piglets (N = 120) were blocked by weight (5.22 ± 0.7 kg) and sex. The pens (n = 5/treatment) within a block were randomly assigned to diets in a 2 × 3 factorial design to examine the effects of Se (0.1 and 0.3 mg/kg added Se) and Mn (0, 12, and 24 mg/kg added Mn) and were fed in three phases (P1 = d 1-7, P2 = d 8-21, P3 = d 22-35). The pigs and orts were weighed weekly. Fecal samples were collected d 0 and 35 for 16S rRNA bacterial gene sequencing and VFA analysis. The data were analyzed as factorial via GLM in SAS. There was a linear response (p < 0.05) in overall ADG across dietary Mn. Supplementing 24 mg/kg Mn tended to decrease (p < 0.10) the relative abundance of many bacteria possessing pathogenic traits relative to Mn controls. Meanwhile, increasing Mn concentration tended to foster the growth of bacteria correlated with gut health and improved growth (p < 0.10). The data from this study provide preliminary evidence on the positive effects of manganese on growth and gut health of nursery pigs.

Hepatopancreatic transcriptome profiles reveal the effects of toxic dietary concentrations of selenium on the immunity and growth of juvenile abalone Haliotis discus hannai

Selenium (Se) is required for the normal growth and development of aquatic animals. However, excessive Se can have various toxic effects on aquatic animals. In this study, we performed transcriptome analysis to determine the mechanism by which immunity and growth of abalone are affected by toxic dietary concentrations of Se. Four experimental diets were administered to supplement organic Se at concentrations of 0.00 (Control), 0.15 (Se15), 0.30 (Se30), and 0.60 mg/kg (Se60) to provide 0.16 (insufficient), 0.32 (optimal), 0.44 (super nutritional), and 0.60 mg/kg (toxic) Se concentrations in the diet. After feeding for 100 days, the results of the Gene Ontology (GO) analysis showed that the enriched GO terms of differentially expressed genes (DEGs) in the Se15 and Se30 groups were mainly focused on the cellular components, whereas the GO terms enriched in the Se60 group were mainly related to the metabolism of nutrients and the activities of various enzymes. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the DEGs of the Se30 group were mainly enriched in various disease pathways, whereas the DEGs of the Se60 treatment were associated with the metabolism of various nutrients. Further analysis of DEGs showed that toxic dietary concentrations of Se decreased the immunity of abalone by affecting the biosynthesis and metabolism pathways of various nutrients. Additionally, toxic dietary concentrations of Se retarded the growth of abalone by decreasing the expression of various genes associated with shell formation, including lustrin A, perlucin, perlustrin, dermatopontin, chitin synthase, and chitinase as well as the genes associated with muscle production, including collagen, myosin heavy chain, myosin essential light chain, and paramyosin. In conclusion, the mechanism of the decrease of immunity and growth of abalone by toxic dietary concentrations of Se has been preliminary revealed in this study.

Growth, Nutrient Retention, Waste Output, and Antioxidant Capacity of Juvenile Triangular Bream (Megalobrama terminalis) in Response to Dietary Selenium Yeast Concentration.

An 8-week feeding trial was conducted to investigate the effects of different dietary selenium yeast levels on growth, nutrient retention, waste output, and antioxidant capacity of juvenile triangular bream (Megalobrama terminalis). Five isonitrogenous (320 g/kg crude protein) and isolipidic (65 g/kg crude lipid) diets were formulated, with supplementation of graded levels of selenium yeast at 0 (diet Se0), 1 (diet Se1), 3 (diet Se3), 9 (diet Se9), and 12 g/kg (diet Se12). No significant differences were found in initial body weight, condition factor, visceral somatic index, hepatosomatic index, and whole body contents of crude protein, ash, and phosphorus among fish fed different test diet. The highest final body weight and weight gain rate were found in fish fed diet Se3. The specific growth rate (SGR) is closely related to dietary selenium (Se) concentrations with a relationship described as SGR = -0.0043 Se2 + 0.1062 Se + 2.661. Higher feed conversion ratio was found, while lower retention efficiencies of nitrogen and phosphorus were found in fish fed diets Se1, Se3, and Se9 than in fish fed diet Se12. Contents of selenium in whole body, vertebra, and dorsal muscle increased with dietary supplementation of selenium yeast increased from 1 mg/kg to 9 mg/kg. Lower nitrogen and phosphorous waste was found in fish fed diets Se0, Se1, Se3, and Se9 than in fish fed diet Se12. Fish fed diet Se3 exhibited the highest activities of superoxide dismutase, glutathione peroxidase, and lysozyme while the lowest malonaldehyde content in both the liver and kidney. Our results showed that the optimal dietary selenium requirement for triangular bream should be 12.34 mg/kg based on the nonlinear regression on SGR, and fish fed diet Se3 in which selenium concentration (8.24 mg/kg) was close to the optimal requirement displayed the best growth performance, feed nutrient utilization, and antioxidant capacity.

Gpx4, Selenov, and Txnrd3 Are Three Most Testis-Abundant Selenogenes Resistant to Dietary Selenium Concentrations and Actively Expressed During Reproductive Ages in Rats.

Almost all selenogenes are expressed in the testis, and those have the highest and constant expressions will be the primary candidates for functional analysis of selenium (Se) in male reproduction. This study aimed to profile the mRNA expressions of the testis-abundant selenogenes of rat models in responses to growth and dietary Se concentrations. Forty-eight weaning SD male rats were fed Se deficient basal diet (BD) for 5weeks and then randomly grouped (n = 12/group) for being fed BD or BD plus 0.25, 3, or 5mg Se/kg for 4 more weeks before sacrifice. Abundances of selenogenomic mRNAs in the liver and testis were determined with relative qPCR and those of the testis-abundant selenogenes in 13 kinds of tissues were assayed with a molecular beacon-based qPCR. Spatiotemporal expressions of rat selenogenome were also analyzed with the RNA-Seq transcriptomic data published by NCBI. mRNA abundances of glutathione peroxidase 4 (Gpx4), nuclear Gpx4 (nGpx4), selenoprotein V (Selenov), and thioredoxin reductase 3 (Txnrd3) in the testis were significantly higher than that in any other tissues (P < 0.05). Moreover, testicular mRNA abundances of Gpx4, Selenov, and Txnrd3 were not affected by levels of dietary Se supplementation (P > 0.05), and much higher at 6-21weeks old than at 2 and 104weeks old (P < 0.05). The result showed that Gpx4, Selenov, and Txnrd3 were most highly expressed in the testis of rats especially at reproductive ages and resistant to the impact of dietary Se levels, which suggested their specific importance in male reproduction.

The Effects of Selenium on Bone Health: From Element to Therapeutics.

Osteoporosis, characterized by low bone mass and a disruption of bone microarchitecture, is traditionally treated using drugs or lifestyle modifications. Recently, several preclinical and clinical studies have investigated the effects of selenium on bone health, although the results are controversial. Selenium, an important trace element, is required for selenoprotein synthesis and acts crucially for proper growth and skeletal development. However, the intake of an optimum amount of selenium is critical, as both selenium deficiency and toxicity are hazardous for health. In this review, we have systematically analyzed the existing literature in this field to determine whether dietary or serum selenium concentrations are associated with bone health. In addition, the mode of administration of selenium as a supplement for treating bone disease is important. We have also highlighted the importance of using green-synthesized selenium nanoparticles as therapeutics for bone disease. Novel nanobiotechnology will be a bridgehead for clinical applications of trace elements and natural products.

Effects of dietary supplementation with different levels of selenium yeast on growth performance, carcass characteristics, antioxidant capacity, and meat quality of Tan sheep

This study was conducted to evaluate the influence of dietary supplementation with different levels of selenium yeast (SeY) on growth performance, carcass characteristics, antioxidant capacity and meat quality of Tan sheep. Sixty-four (n = 64) five-month-old male Tan sheep with an initial body weight of 32 ± 1.95 kg (BW ± SD) were selected and randomly assigned to four treatments with 16 replicates of one sheep each. The four groups received a basal diet (0.16 mg Se/kg) supplemented with 28.94, 105.46, 258.51, 564.60 mg/kg SeY to final dietary selenium (Se) concentrations of 0.25 (Se0.25), 0.5 (Se0.5), 1.0 (Se1.0), or 2.0 (Se2.0) mg/kg for 60 days, respectively. The feed-to-weight gain ratio showed a quadratic significant change of first increasing and then decreasing with the increase of dietary SeY supplemental level (p<0.01). Dietary Se at >0.25 mg/kg markedly decreased the GR value of the sheep (p<0.05). Thioredoxin reductase activity in sheep serum was markedly higher in the Se0.5 group (p<0.05) and glutathione peroxidase activity in sheep liver was significantly higher in the Se1.0 group (p<0.01), and both began to decline afterwards. Dietary Se at >0.25 mg/kg significantly enhanced muscle thioredoxin reductase activity (p<0.05) and decreased the content of thiobarbituric acid reactive substances in the liver and muscle tissues (p<0.01). Different supplementary levels of SeY had no significant effect on pH values at 45 min and 24 h postmortem (p>0.05). Moreover, final dietary Se at >0.25 mg/kg was associated with significant decreases in the lightness and yellowness values of muscle tissues at 45 min (p<0.01), but had no obvious effect on the redness value (p>0.05). Meat color of mutton had a less change over time in the Se0.5 group, and the color stability was better. Drip loss of muscle decreased significantly with an increase in dietary SeY supplementation (p<0.05). In general, dietary supplemented with SeY to a final Se concentration of 0.5–1.0 mg/kg can maintain antioxidant capacity at a high level and obtain better meat quality of Tan sheep. The results of this study pave the way for the rational application of Se in the feed of Tan sheep.

Addition of Bamboo Charcoal to Selenium (Se)-Rich Feed Improves Growth and Antioxidant Capacity of Blunt Snout Bream (Megalobrama amblycephala).

Simple SummaryIn our previous studies, we determined that juvenile blunt snout bream (Megalobrama amblycephala) require a selenium (Se) dietary intake of 0.958–0.959 mg/kg based on the quadratic fitting method. Nevertheless, growth rates were significantly affected, and the expression of anti-inflammatory factors was inhibited when the feed contained excessively high Se concentrations. Given its activity as an insoluble carrier, bamboo charcoal can be used as a dietary supplement in fish feed to absorb and slowly release excess nutrients. However, these hypotheses have not been evaluated in diets containing excess Se. The present study determined that 2–3 g/kg bamboo charcoal inclusion in Se-rich feed could improve the growth performance of blunt snout bream. Dietary bamboo charcoal supplementation mobilized the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 signaling while suppressing NF-κB signaling.The ability of bamboo charcoal to reduce the negative effects of high dietary selenium (Se) concentrations was assessed by feeding juvenile blunt snout bream (Megalobrama amblycephala) one of five Se-rich diets (1.5 mg/kg Se; 36% protein, 8.7% lipid) containing graded levels (0–4 g/kg) of bamboo charcoal powder for eight weeks. There were four tanks (350 L) of fish (initial weight 16.0 ± 0.5 g) for each treatment, and the fish were fed to satiation four times each day. At the end of the feeding trial, all of the fish from each tank were weighed to calculate the growth performance. Blood samples were firstly obtained to collect plasma for the biochemical indexes determination. Liver tissues were then collected to determine the antioxidant enzyme activities and gene expression. Dorsal muscles were also collected to determine the nutrient composition. The results show that when the bamboo charcoal content in the Se-rich feed ranged between 0 and 3 g/kg, the weight growth rate (WGR) and specific growth rate (SGR) values increased with the higher dietary bamboo charcoal content, and the maximum WGR and SGR values were achieved when the bamboo charcoal content in the Se-rich feed was 2–3 g/kg (p < 0.05). The Se content in muscle tissues decreased significantly with the increased bamboo charcoal content (p < 0.05) in the Se-rich feed, which ranged from 0 to 4 g/kg. When the bamboo charcoal content in the Se-rich feed was 2–3 g/kg, the levels of glucose (GLU) and albumin (ALB) in plasma reached a maximum (p < 0.05), whereas the level of alkaline phosphatase (ALP) reached a minimum (p < 0.05). Additionally, the activities of catalase (CAT), total superoxide dismutase (T-SOD), total antioxidative capacity (T-AOC), and glutathione peroxidase (GSH-Px) were significantly enhanced (p < 0.05) when the bamboo charcoal content was 3 g/kg. In contrast, the malondialdehyde (MDA) level increased sharply when the bamboo charcoal content in the Se-rich feed was 1 g/kg, compared to the control group and the groups supplemented with 2–3 g/kg bamboo charcoal (p < 0.05). Regarding mRNA-level gene expression, the results show that dietary supplementation with 0 to 3 g/kg of bamboo charcoal increased the expression of keap1 and nrf2, whereas nfkb expression was inhibited (p < 0.05). The mRNA expression of the antioxidant enzymes cat, gpx, and mn-sod was consistently enhanced in the group fed with the 3 g/kg bamboo charcoal diet (p < 0.05). The expression of the pro-inflammatory cytokines tnfα and tgfβ was inhibited in the groups supplemented with 2–3 g/kg bamboo charcoal, whereas the expression of anti-inflammatory cytokines (il10) increased in the bamboo charcoal supplementation groups compared to the control group (p < 0.05). Generally, supplementation with 2–3 g/kg of bamboo charcoal in Se-rich feed improved the growth performance, physiological status, and antioxidant enzyme activities of blunt snout bream. Moreover, bamboo charcoal supplementation in Se-rich diets stimulated the antioxidant system and inhibited the inflammatory response by activating Nrf2-Keap1 and suppressing NF-κB.

Selenium status and its relationship with thyroid hormones in obese women.

Studies have been conducted with the purpose of elucidating thyroid gland dysfunction in obesity, however the contributing factors for such dysfunction are not yet fully understood. Selenium is notable for its role in thyrocyte protection against oxidative damage and control of thyroid hormone synthesis. In addition, subjects with obesity may exhibit alterations in the selenium homeostasis. Therefore, the present study aimed to examine the selenium status and its relationship with serum thyroid hormone levels in obese women. This cross-sectional study included 69 euthyroid women, aged between 18 and 50 years, who were divided in two groups: an obese group (n=35) and a control group with women of normal weight (n=34). Selenium intake was assessed by three-day diet records and analyzed using NutWin software version 1.5. Plasma, erythrocyte, and urinary selenium levels were determined using inductively coupled plasma optical emission spectrometry. Testing for thyroid hormones and thyroid autoantibodies was performed based on chemiluminescence. The median dietary selenium content was adequate according to the recommendations, with no statistical difference between groups. Obese women had reduced plasma and erythrocyte selenium levels compared to the control group, although selenium concentration in erythrocytes was adequate within the normal range for both groups. There was no significant difference between the urinary selenium concentrations in the subjects; however, the mineral clearance was higher in the obese group. Free triiodothyronine (fT3) and free thyroxine (fT4) levels were higher in obese women with class II obesity when compared to the control group. There was a negative correlation between plasma selenium and serum fT4 levels. Obese women showed impairment in selenium homeostasis, however, this fact did not seem to adversely affect thyroid metabolism.

Association of dietary and serum selenium concentrations with glucose level and risk of diabetes mellitus: A cross sectional study of national health and nutrition examination survey, 1999-2006

BackgroundThe associations among dietary selenium intake, serum selenium concentration, plasma glucose and glycosylated hemoglobin levels, and diabetes risk remain controversial. This study aimed to evaluate these associations in adults from the United States. MethodsWe conducted a cross-sectional study of participants aged 18 years and older who participated in the National Health and Nutrition Examination Survey. Between 1999 and 2006, a total of 41,474 participants were initially included in this study. Multivariable linear or logistic regression analysis was used to investigate the association between dietary selenium intake and serum selenium concentrations, glucose level, and diabetes risk. ResultsThe average age of the participants was 30.32 ± 23.95 years, and 48.72 % were men. Their mean dietary selenium intake and mean serum selenium concentration were 98 ± 55 μg per day and 129 ± 22 ng/mL, respectively. Compared with t he lowest quartile of dietary selenium intake, the highest quartile was associated with elevated plasma glucose levels (β = 2.412, 95 % confidence interval [CI]: 0.420, 4.403, P = 0.018), glycosylated hemoglobin levels (β = 0.080, 95 % CI: 0.041, 0.119, P < 0.001), and diabetes risk (odds ratio [OR] = 2.139, 95 % CI: 1.763, 2.596, P < 0.001). Higher serum selenium was also associated with increased plasma glucose levels (β = 12.454, 95 % CI: 4.122, 20.786, P = 0.003) and glycosylated hemoglobin levels (β = 0.326, 95 % CI: 0.187, 0.465, P < 0.001). A generalized additive model with a spline curve suggested a nonlinear relationship between dietary selenium intake, serum selenium and glucose levels, and diabetes risk. ConclusionsDietary selenium intake and serum selenium were positively associated with elevated levels of plasma glucose and glycosylated hemoglobin, and the relationships were nonlinear. Additional selenium supplementation for patients with diabetes may not be recommended.

Knockout of Selenoprotein V Affects Regulation of Selenoprotein Expression by Dietary Selenium and Fat Intakes in Mice

Background:The metabolic function of selenoprotein V (SELENOV) remains unknown. Objectives:Two experiments were conducted to determine effects of the Selenov knockout (KO) on selenium concentration and mRNA, protein, and/or activity of 4 major selenoproteins [glutathione peroxidase (GPX) 1, GPX4, thioredoxin reductase-1 (TXNRD1), and selenoprotein P (SELENOP)] in the serum, liver, testis, and/or white adipose tissue (WAT) of mice fed different dietary selenium and fat concentrations. Methods:In Experiment (Expt) 1, 40 KO and 40 wild-type (WT) mice (males, 8 wk old) were fed (n= 10/genotype) a casein-sucrose basal diet plus 0, 0.3, 1, or 3 mg Se/kg (as sodium selenite) for 32 wk . In Expt 2, 20 KO and 20 WT mice (males, 8 wk old) were fed (n = 10/genotype) a normal-fat diet (NF; 10% calories from fat) or a high-fat diet (HF; 60% calories from fat) for 19 wk. Results:In Expt 1, the KO caused consistent or substantial decreases (P < 0.05) of mRNA amounts of Gpx1, Txnrd1,and Selenop in the testis (≤52%), but selenium concentrations (19–29%) and GPX activities (≤ 50%) were decreasedin the liver across different dietary selenium concentrations . Hepatic and testis GPX1 protein was elevated (≤31%) anddecreased (≤45%) by the KO, respectively. In Expt 2, the genotype and dietary fat intake exerted interaction effects (P < 0.05) on Gpx1 mRNA amounts in the WAT; Gpx1, Txnrd1, and Selenop mRNA amounts and TXNRD activities in thetestis; and selenium concentrations in the serum and liver. However, these 2 treatments produced largely independentor additive effects (P < 0.05) on the GPX1 and SELENOP protein amounts in the liver and testis (up to } 50% changes) Conclusions:The KO-mediated changes in the tissue selenium concentrations and functional expression of 3 major selenoproteins implied potential for SELENOV in regulating body selenium metabolism in the mouse.

Dietary and serum selenium in coronary heart disease and all-cause mortality: An international perspective.

The objective of this study was to explore the associations of dietary selenium and serum selenium concentration with coronary heart disease (CHD) prevalence and all-cause mortality among participants in United States. Using data collected from the National Health and Nutrition Examination Survey (NHANES) 1999-2006, 17867 individuals were included. Logistic regression analyses were used to explore the associations between dietary selenium intake and serum selenium concentration and prevalent of CHD. Multivariable Cox regression was used to identify the association between dietary selenium intake and all-cause mortality. The nonlinear relationships were assessed using generalized additive models. A U-shaped association between dietary intake of selenium and all-cause mortality was observed. Compared with the lowest quartile, the second quartile of dietary intake of selenium was inversely associated with all-cause mortality (Hazard ratio [HR]: 0.802, 95% confidence interval [CI]: 0.658, 0.977, p=0.029). There was no evidence of association between dietary selenium intake and CHD risk (Odds ratio [OR]: 1.001, 95% CI: 0.999, 1.003, p=0.206). Furthermore, serum selenium concentration was negatively associated with CHD risk (OR: 0.989, 95% CI: 0.981, 0.997, p=0.006). Comparing with the lowest quartile, participants with the highest serum selenium concentration had a statistically significant decreased prevalence of CHD, with OR (95% CI) of 0.417 (0.259, 0.669) (p<0.001). The smoothing curve also showed a non-linear relationship between serum selenium and risk of CHD. This analysis suggested that a higher serum selenium concentration was associated with reduced risk of CHD, and that the relationship was non-linear. In addition, an appropriate dietary selenium intake might reduce all-cause mortality.

Supplemental hot melt extruded nano-selenium increases expression profiles of antioxidant enzymes in the livers and spleens of weanling pigs

A study was conducted to determine the effect of dietary selenium (Se) concentration and source for weanling pigs on serum Se, glutathione peroxidase (GPx) activity and performance. A total of 120 weanling pigs with an average weight of 6.87 ± 0.4 kg were assigned to 4 diets with 10 pigs per cage and 3 replicates per treatment. The experimental diets were fed for 28 days in 2 phases (phase 1, d 0–14; and phase 2, d 15–28). Treatments were: Control (without Se supplementation), sodium selenite (INO; 0.30 ppm), hot melt extruded sodium selenite (HME; 0.30 ppm), and selenomethionine (ORG; 0.3 ppm). There were significant responses (P < 0.05) for higher serum Se concentration in the HME and ORG treatments in phase 1 and 2. The serum GPx analyses revealed that supplemental HME and ORG significantly increased the concentration of GPx in the serum in phase 1 and phase 2. There was an up-regulated (P < 0.01) expression of Selenoprotein W, GPx1, GPx3, GPx4, and GPx5 in the livers of the HME and ORG pigs. In conclusion, the HME and ORG Se showed increased antioxidant status, consequently being a more suitable source of Se than regular sodium selenite.

Biological Evaluation of Hot-Melt Extruded Nano-selenium and the Role of Selenium on the Expression Profiles of Selenium-Dependent Antioxidant Enzymes in Chickens.

A study was conducted to determine the effect of dietary selenium (Se) concentration and source for broiler chickens on performance, nutrient digestibility, plasma Se, glutathione peroxidase (GPx) activity, and thiobarbituric acid reactive substances (TBARS). A total of 700 1-day-old broiler chicks were assigned to 7 diets with 20 birds per cage and 5 replicates per treatment. The experimental diets were fed for 32days in 2 phases (phase 1, day 0 to 14 and phase 2, day 15 to 32). Treatments were as follows: control (without Se supplementation), sodium selenite (SeS; 0.15, 0.30, or 0.45ppm), and hot-melt extruded sodium selenite (SeHME; 0.15, 0.30, or 0.45ppm). There were significant linear responses (P< 0.01) for higher plasma Se concentration in SeS and SeHME treatments. Moreover, an increased (P< 0.01) Se concentration of plasma occurred in SeHME treatment compared with that in SeS treatment. The serum GPx analyses revealed that supplemental SeS and SeHME increased significantly the activity of GPx in the plasma in phase 1 (P< 0.05) and phase 2 (P< 0.05). There were significant linear (P< 0.01) responses of SeS and SeHME treatments for the expression of SelW, GPx1, GPx3, and GPx4 in the livers and spleens. In addition, SeHME showed an upregulated expression of GPx-4 in the livers (P< 0.01) and SelW in the spleens (P< 0.05) compared with SeS treatment. SeHME showed a lower TBARS on day 9. Moreover, a decreased (P< 0.01) TBARS occurred in SeS treatment compared with that in control treatment. In conclusion, SeHME can increase antioxidant activity and Se absorption, consequently being a more suitable source of Se than regular sodium selenite.

Effects of dietary selenium and moisture on the physical activity and thyroid axis of cats.

Consumption of canned cat food is considered a risk factor for the development of feline hyperthyroidism. Because selenium and water are substantially higher in canned diets compared to dry diets, objectives of this study were to determine whether increased dietary selenium or water alters the function of the hypothalamic-pituitary-thyroid axis and leads to an increase in activity level. Employing a 28-day latin square design with a 14-day washout, six lean, neutered male domestic shorthair cats were fed (i) commercially available adult dry feline diet containing 0.8ppm selenium (control), (ii) control diet with added sodium selenite to achieve a dietary selenium concentration of 1.125ppm (selenium treatment) and (iii) the control diet with additional water to achieve a moisture content of 75% wt/wt (water treatment). Water consumption was determined using deuterium oxide washout. Actical activity monitors were placed on each cat's collar to allow quantification of the activity of each cat. Circulating serum T3 and T4 was measured on days 0, 14, and 28. On day 28, a thyrotropin-releasing hormone (TRH) stimulation test was conducted to determine treatment effects on serum concentrations of thyroid hormones. There was a significant increase in daily water consumption with dietary water treatment (192ml±7.85 SEM) compared to the control (120ml±20.4) and selenium (116ml±14.6) treatments. Both water and selenium treatments were associated with greater (p<.05) activity over that of the control treatment by 20.5% and 11% respectively. Serum TT3 AUC concentrations (0-4hr) of TRH stimulation tests were greater (p<.05) by 16% with water compared to control treatments. The results of this study indicate that dietary water content may alter the function of the thyroid axis and that this effect is associated with an increase in physical activity.

Dietary Selenium Deficiency or Excess Reduces Sperm Quality and Testicular mRNA Abundance of Nuclear Glutathione Peroxidase 4 in Rats

Background: Glutathione peroxidase (GPX) 4 and selenoprotein P (SELENOP) are abundant, and several variants are expressed in the testis.Objective: We determined the effects of dietary selenium deficiency or excess on sperm quality and expressions of GPX4 and SELENOP variants in rat testis and liver.Methods: After weaning, male Sprague-Dawley rats were fed a Se-deficient basal diet (BD) for 5 wk until they were 9 wk old [mean ± SEM body weight (BW) = 256 ± 5 g]. They were then fed the BD diet alone (deficient) or with 0.25 (adequate), 3 (excess), or 5 (excess) mg Se/kg for 4 wk. Testis, liver, blood, and semen were collected to assay for selenoprotein mRNA and protein abundances, selenium concentration, GPX activity, 8-hydroxy-deoxyguanosine concentration, and sperm quality.Results: Dietary selenium supplementations elevated (P < 0.05) tissue selenium concentrations and GPX activities. Compared with those fed BD + 0.25 mg Se/kg, rats fed BD showed lower (P < 0.05) BW gain (86%) and sperm density (57%) but higher (P < 0.05) plasma 8-hydroxy-deoxyguanosine concentrations (189%), and nonprogressive sperm motility (4.4-fold). Likewise, rats fed BD + 5 mg Se/kg had (P = 0.06) lower BW gain and higher (1.9-fold) sperm deformity rates than those in the selenium-adequate group. Compared with the selenium-adequate group, dietary selenium deficiency (BD) or excess (BD + 3 or 5 mg Se/kg) resulted in 45-77% lower (P < 0.05) nuclear Gpx4 (nGpx4) mRNA abundance in the testis. Rats fed BD had lower (P < 0.05) mRNA levels of 2 Selenop variants in both testis and liver than those in the other groups. Testicular SELENOP was 155-170% higher (P < 0.05) in rats fed BD + 5 mg Se/kg and hepatic c/mGPX4 was 13-15% lower (P < 0.05) in rats fed BD than in the other groups.Conclusions: The mRNA abundance of rat testicular nGPX4 responded to dietary selenium concentrations in similar ways to sperm parameters and may be used as a sensitive marker to assess appropriate Se status for male function.

Growth, antioxidant capacity and muscle histochemistry of yellowtail kingfish (Seriola lalandi Valenciennes 1883): Selenium and temperature interaction

The aim of this study was to investigate the interactive effects of temperature and dietary selenium concentrations on antioxidant capacity, muscle histochemistry and the growth, of juvenile yellowtail kingfish (Seriola lalandi). The yellowtail kingfish were exposed to two temperatures (21°C or 26°C) and three selenium levels (0.0, 2.0 or 4.0mgSekg−1 of feed) for 30 days. Final weight and specific growth rate (SGR) were significantly affected by water temperature (ρ<0.001) and dietary Se (ρ<0.001) supplementation, and there were significant differences in the interaction between these two factors. Juvenile yellowtail kingfish fed Se-supplemented diets, attained a higher final weight and SGR than those without Se supplementation at 21°C, but not at 26°C. Regardless of the temperature, the red blood cell (RBC) glutathione peroxidase (GPx) activity of yellowtail kingfish fed Se-supplemented diets was significantly higher (ρ<0.05) than with the control diet. However, GPx activity of yellowtail kingfish when fed either 2.0mgSekg−1 or 4.0mgSekg−1 showed no significant difference (ρ>0.05). Se concentration in the muscles of juvenile yellowtail kingfish fed Se-supplemented diets was higher than that of the yellowtail kingfish that were fed the control diet. A histopathological test confirmed that 20.3% of fish muscles exhibited lesions, which occurred in the absence of dietary Se. The outcome of the present study helps in understanding the interactive effects of dietary Se concentrations and the temperature in the farming of yellowtail kingfish.

The effect of dietary fat, vitamin E and selenium concentrations on the fatty acid profile and oxidative stability of frozen stored broiler meat

A total of 160 Ross 308 female broilers from day 22 to 35 of age were used to investigate the effects of vitamin E and selenium (Se) supple- mentation on performance, fatty acid profile and oxidative stability of meat en - riched with n-3 fatty acids. There were 4 treatment groups, 3 diets contained rape seeds and fish oil (60 and 15 g · kg -1 , respectively - RF), the control diet contained animal fat - lard. To the RF diet different doses of vitamin E and Se were added (80 and 0.3, 150 and 0.3, 150 and 0.7 mg per kilogram of diet, re- spectively). Performance was measured and samples of breast and thigh meat were vacuum packed and stored at -30°C. The concentration of thiobarbituric acid reactive substances (TBARS) was determined after 3 weeks and after 3 months of frozen storage, when also fatty acid profiles, vitamin E and choles - terol contents in meat were measured. Body weight gain and feed conversion ratio were negatively influenced ( P ≤ 0.05) by the increased dietary level of Se. Feeding diets with rape seeds and fish oil resulted in higher concentrations and lower n-6/n-3 PUFA ratios in breast and thigh meat (P ≤ 0.05) compared with the control. The increase of dietary vitamin E, but not Se, increased the tocopherol content in meat and reduced TBARS values in 3-month-stored thigh meat (P ≤ 0.05). It may be concluded that fortification of diets with vitamin E increases its concentration in, and oxidative stability of frozen stored breast and thigh meat, but no additional benefit was observed in feeding excess Se in combination with vitamin E.

Antioxidant capacity total in non-melanoma skin cancer and its relationship with food consumption of antioxidant nutrients.

The non-melanoma skin cancer is the most common cancer and accounts for more than half of the diagnoses of cancer, and basal cell carcinoma (BCC), the most frequent cutaneous neoplasm, corresponding to 70-80% of cutaneous tumors. Oxidative stress is an important trigger for skin carcinogenesis. Thus, it is important to evaluate oxidative stress, in order to discern effective therapeutic strategies able to stop it or attenuate it, thereby prevent the installation of non-melanoma skin cancer. Cross-sectional study with controls, involving 84 individuals of both sexes aged between 38-84 years, divided into two groups: control group of healthy people(n = 24) and the case group included individuals who presented non-melanoma skin and they have undergoing surgery (n = 60). The blood samples of the individuals were obtained for evaluation of biomarkers of oxidative stress (F2-isoprostane, nitrite, thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity). The usual dietary intake and nutritional status of the subjects were evaluated. The significance level for this study was 5%. Patients in the case group had higher serum concentrations of biomarkers of oxidative stress, F2-isoprostane concentrations were significantly higher compared to controls. The results showed high rates of overweight and obesity in the case and control groups. The dietary concentrations of antioxidant minerals zinc, copper and selenium in the case group were significantly lower compared to controls. The correlation between markers of oxidative stress and dietary concentrations of antioxidant nutrients showed the influence of food intake of vitamins A and E in reducing oxidative stress, since these nutrients behave as important antioxidants, acting as sweepers of RL, by removing of the body the negative effects on the redox balance of the skin. We emphasize the importance of adopting healthy eating habits that optimize the consumption of antioxidant nutrients as a strategy to prevent oxidative damage to the skin.

Effects of organic selenium supplementation on growth performance, nutrient utilisation, oxidative stress and selenium tissue concentrations in broiler chickens

The effects of organic selenium (Se) supplementation of diets for broiler chickens were evaluated in the present study. Broiler diets had average background Se concentrations of 0.36 mg/kg Se (control diet) and were supplemented with two organic Se sources, namely BiOnyc® Tor-Sel (selenohomolanthionine = SH) and Alltech’s Sel PlexTM (selenomethionine = SM); their addition increased dietary selenium concentrations by an average of 0.57 mg/kg Se. Their effects on growth performance, nutrient utilisation and oxidative status of broiler chickens were determined. Growth performance was very similar across all dietary treatments; in contrast, significant differences in nutrient utilisation were observed. The N-corrected apparent metabolisable energy value for the control group (14.14 MJ/kg) and SH (14.15 MJ/kg) diet was significantly (P &lt; 0.01) higher than that for the SM (13.64 MJ/kg) diet. Alternatively, N retention with the SM (68.4%) diet was significantly (P &lt; 0.005) higher than that for the control (65.2%) and SH (64.5%) diets. Neither of the Se sources influenced plasma concentrations of reactive oxygen metabolites, biological antioxidant potential and advanced oxidation protein products. The activity of glutathione peroxidase, superoxide dismutase in both plasma and tissues samples and the concentration of plasma glutathione were increased by SH and SM compared with the control group. Our findings suggest that SH and SM improved the antioxidant status of broilers by elevating activities of antioxidant enzymes and concentrations of antioxidant. Both Se supplements significantly (P &lt; 0.001) increased Se concentrations in liver and muscle, and in liver tissue there was no statistical difference between the two supplements. However, SH generated significantly higher Se concentrations in muscle tissue (0.283 versus 0.257; P &lt; 0.005) than did SM. In summary, SH was at least the equivalent to SM as a source of organic Se for broiler chickens under the conditions of the present feeding study. This is reflected in the outcome that SH generated significantly higher Se concentrations in muscle tissue than did the alternative Se supplement.